Mary Tobin

Lamont Doherty Scientists Size Up Plattsburgh Earthquake

Click HERE to see maps, seismograms and data from the Lamont-Doherty Cooperative Seismographic Network (LCSN).

Detail from a seismogram, showing the mainshock in red.

Three teams of Lamont Doherty Earth Observatory seismologists are in Plattsburgh, New York, this week assessing damage due to the largest earthquake to hit New York State and New England in the last 19 years.

The teams also are deploying portable seismographs in the vicinity of the mainshock epicenter, about 29 km (17 miles) southwest of Plattsburgh. These state-of-the-art instruments can detect the weaker vibrations associated with the aftershocks of the main event. The characteristics of the aftershock sequence will help seismologists to determine which fault was responsible for the mainshock. The data will also be useful to structural engineers for determining the amplitude of the shock waves we can expect from future earthquakes in the Northeast. Because of the importance of studying such a large, rare event, the United States Geological Survey (USGS) is supporting the aftershock survey.

Registering 5.1 in magnitude, and centered in Plattsburgh, the quake was felt up and down the Northeast coast around 6:50 a.m., last Saturday, April 20, 2002. A permanent seismic monitoring network operated by Columbia's Lamont Doherty Earth Observatory (LDEO) recorded it as it struck.

LDEO is a member of the Advanced National Seismic System of the U.S. Geological Survey, or ANSS, and bears the responsibility for monitoring and reporting earthquakes in New York and other states in the Northeast. LDEO partners with other institutions, such as the Weston Observatory of Boston College, the Delaware Geological Survey, and several universities, colleges and high schools, in order to maintain the monitoring system. The Weston Observatory shares leadership responsibilities with LDEO.

Seismologists from Geological Survey of Canada, Carleton University of Ottawa, and the Center for Earthquake Research and Information at the University of Memphis are collaborating with the Lamont team. Additional instrumentation has also been supplied by the Incorporated Resesarch Insitutions for Seismology (IRIS), a consortium of more than 90 universities with research programs in seismology.

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